For a lousy looker like me, given the aspect of some of the sections as looking real old, pommel (plus peen fixation) and all, the blade inscription is so crisp that it could (could) have been made at a later stage
.
On the other hand, when you play with values, you are certainly aware that, the difference in value (read price) between a Victorian item and a XVII century one, is abyssal; independently from what Norman withdrew from his sporran to catch this one.
Hopefully Jasper comes around and give a honest and capable opinion on this piece.